BOTHELL, Wash.--(BUSINESS WIRE)--Nov. 2, 2017--
Seattle
Genetics, Inc. (NASDAQ:SGEN) announced today that it has submitted a
supplemental Biologics License Application (BLA) to the U.S. Food and
Drug Administration (FDA) based on data from the phase 3 ECHELON-1 trial
evaluating ADCETRIS (brentuximab vedotin) in combination with
chemotherapy for the frontline treatment of patients with advanced
classical Hodgkin lymphoma. ADCETRIS is an antibody-drug conjugate (ADC)
directed to CD30, a defining marker of classical Hodgkin lymphoma.
ADCETRIS is being evaluated globally as the foundation of care for
CD30-expressing lymphomas in more than 70 corporate- and
investigator-sponsored clinical trials. ADCETRIS is currently not
approved as a frontline therapy for Hodgkin lymphoma.

“There have been no new treatment advances for frontline Hodgkin
lymphoma in more than 40 years. Up to 30 percent of the patients
diagnosed with advanced disease will experience disease progression
after frontline treatment with the current standard of care chemotherapy
regimen, representing a significant unmet need to improve the treatment
outcome of these patients who are often young adults,” said Clay
Siegall, Ph.D., President and Chief Executive Officer of Seattle
Genetics. “Results from the ECHELON-1 study demonstrated superior
activity of an ADCETRIS-containing regimen over standard of care, and
resulted in FDA Breakthrough Therapy Designation for ADCETRIS in
combination with chemotherapy for frontline advanced classical Hodgkin
lymphoma. We believe these data represent a significant advance for the
patient and physician community and look forward to working with the FDA
to complete the review of this new treatment regimen as quickly as
possible.”

The ECHELON-1 study evaluated a combination of ADCETRIS plus AVD
(Adriamycin, vinblastine, dacarbazine) compared to a recognized standard
of care chemotherapy regimen, ABVD (which also includes bleomycin), in
previously untreated advanced classical Hodgkin lymphoma. The ECHELON-1
study met its primary endpoint of a statistically significant
improvement in modified progression-free survival (PFS) of the ADCETRIS
containing regimen versus the control arm as assessed by an Independent
Review Facility (hazard ratio=0.770; p-value=0.035). The two-year
modified PFS rate for patients in the ADCETRIS arm was 82.1 percent
compared to 77.2 percent in the control arm. Interim analysis of overall
survival, the key secondary endpoint, also trended in favor of the
ADCETRIS plus AVD arm. The safety profile of ADCETRIS plus AVD in the
ECHELON-1 trial was consistent with that known for the single-agent
components of the regimen. Full data from the ECHELON-1 study will be
presented in the Plenary Scientific Session at the American Society of
Hematology (ASH) Annual Meeting on Sunday, December 10, 2017 from 2:00 –
4:00 p.m. ET in Atlanta, Georgia.

ADCETRIS was recently granted Breakthrough Therapy Designation by the
FDA based on data from the phase 3 ECHELON-1 clinical trial. The FDA’s
Breakthrough Therapy Designation is intended to expedite the development
and review of promising drug candidates for serious or life-threatening
conditions. It is based upon clinical evidence of substantial
improvement over existing therapies on one or more clinically
significant endpoints.

ECHELON-1 Phase 3 Clinical Trial Design

The randomized, open-label, phase 3 trial is investigating ADCETRIS plus
AVD versus ABVD as frontline therapy in patients with advanced classical
Hodgkin lymphoma. The primary endpoint is modified PFS per Independent
Review Facility assessment using the Revised Response Criteria for
Malignant Lymphoma. Modified PFS is defined as the time to progression,
death or receipt of additional anticancer therapy for patients who are
not in complete response after completion of frontline therapy per
Independent Review Facility. This endpoint was chosen as it provides a
clearer picture of the efficacy of frontline chemotherapy and eliminates
the confounding impact of salvage and consolidation chemotherapies and
radiotherapy. Secondary endpoints include overall survival, complete
remission and safety. The multi-center trial was conducted in North
America, Europe, South America, Australia, Asia and Africa. The study
enrolled 1,334 patients who had a histologically-confirmed diagnosis of
Stage III or IV classical Hodgkin lymphoma and had not been previously
treated with systemic chemotherapy or radiotherapy. The ECHELON-1 trial
is being conducted under a Special Protocol Assessment (SPA) agreement
from the FDA and the trial also received European Medicines Agency (EMA)
scientific advice.

Please see Important Safety Information at the end of this press release.

About Classical Hodgkin Lymphoma

Lymphoma is a general term for a group of cancers that originate in the
lymphatic system. There are two major categories of lymphoma: Hodgkin
lymphoma and non-Hodgkin lymphoma. Classical Hodgkin lymphoma is
distinguished from other types of lymphoma by the presence of one
characteristic type of cell, known as the Reed-Sternberg cell. The
Reed-Sternberg cell expresses CD30.

According to the American Cancer Society, approximately 8,260 cases of
Hodgkin lymphoma will be diagnosed in the United States during 2017 and
more than 1,000 will die from the disease. According to the Lymphoma
Coalition, over 62,000 people worldwide are diagnosed with Hodgkin
lymphoma each year and approximately 25,000 people die each year from
this cancer.

About ADCETRIS

ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30 and is
being evaluated broadly in more than 70 clinical trials, including four
phase 3 studies: the ECHELON-1 trial in frontline classical Hodgkin
lymphoma from which positive top-line results were recently reported and
the FDA granted Breakthrough Therapy Designation in this setting, the
ongoing ECHELON-2 trial in frontline mature T-cell lymphomas, the
completed ALCANZA trial in cutaneous T-cell lymphoma that supported the
supplemental BLA with a Prescription Drug User Fee Act (PDUFA) target
action date of December 16, 2017, and the recently initiated CHECKMATE
812 trial of ADCETRIS in combination with Opdivo (nivolumab) for
relapsed/refractory Hodgkin lymphoma.

ADCETRIS is an ADC comprising an anti-CD30 monoclonal antibody attached
by a protease-cleavable linker to a microtubule disrupting agent,
monomethyl auristatin E (MMAE), utilizing Seattle Genetics’ proprietary
technology. The ADC employs a linker system that is designed to be
stable in the bloodstream but to release MMAE upon internalization into
CD30-expressing tumor cells.

ADCETRIS for intravenous injection has received FDA approval for three
indications: (1) regular approval for the treatment of patients with
classical Hodgkin lymphoma after failure of autologous hematopoietic
stem cell transplantation (auto-HSCT) or after failure of at least two
prior multi-agent chemotherapy regimens in patients who are not
auto-HSCT candidates, (2) regular approval for the treatment of
classical Hodgkin lymphoma patients at high risk of relapse or
progression as post-auto-HSCT consolidation, and (3) accelerated
approval for the treatment of patients with systemic anaplastic large
cell lymphoma (sALCL) after failure of at least one prior multi-agent
chemotherapy regimen. The sALCL indication is approved under accelerated
approval based on overall response rate. Continued approval for the
sALCL indication may be contingent upon verification and description of
clinical benefit in confirmatory trials.

Health Canada granted ADCETRIS approval with conditions for relapsed or
refractory Hodgkin lymphoma and sALCL in 2013, and non-conditional
approval for post-ASCT consolidation treatment of Hodgkin lymphoma
patients at increased risk of relapse or progression.

ADCETRIS was granted conditional marketing authorization by the European
Commission in October 2012 for two indications: (1) for the treatment of
adult patients with relapsed or refractory CD30-positive Hodgkin
lymphoma following autologous stem cell transplant (ASCT), or following
at least two prior therapies when ASCT or multi-agent chemotherapy is
not a treatment option, and (2) the treatment of adult patients with
relapsed or refractory sALCL. The European Commission extended the
current conditional marketing authorization of ADCETRIS and approved
ADCETRIS for the treatment of adult patients with CD30-positive Hodgkin
lymphoma at increased risk of relapse or progression following ASCT.

ADCETRIS has received marketing authorization by regulatory authorities
in 68 countries for relapsed or refractory Hodgkin lymphoma and sALCL.
See important safety information below.

Seattle Genetics and Takeda are jointly developing ADCETRIS. Under the
terms of the collaboration agreement, Seattle Genetics has U.S. and
Canadian commercialization rights and Takeda has rights to commercialize
ADCETRIS in the rest of the world. Seattle Genetics and Takeda are
funding joint development costs for ADCETRIS on a 50:50 basis, except in
Japan where Takeda is solely responsible for development costs.

About Seattle Genetics

Seattle Genetics is an innovative biotechnology company dedicated to
improving the lives of people with cancer through novel antibody-based
therapies. The company’s industry-leading antibody-drug conjugate (ADC)
technology harnesses the targeting ability of antibodies to deliver
cell-killing agents directly to cancer cells. Seattle Genetics
commercializes ADCETRIS® (brentuximab vedotin) for the
treatment of several types of CD30-expressing lymphomas. The company is
also advancing a robust pipeline of novel therapies for solid tumors and
blood-related cancers designed to address significant unmet medical
needs and improve treatment outcomes for patients. More information can
be found at www.seattlegenetics.com
and follow @SeattleGenetics on Twitter.

ADCETRIS (brentuximab vedotin) U.S. Important Safety Information

BOXED WARNING: PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY (PML)

JC virus infection resulting in PML and death can occur in
ADCETRIS-treated patients.

Anaphylaxis and infusion reactions: Infusion-related reactions
(IRR), including anaphylaxis have occurred with ADCETRIS. Monitor
patients during infusion. If an IRR occurs, interrupt the infusion and
institute appropriate medical management. If anaphylaxis occurs,
immediately and permanently discontinue the infusion and administer
appropriate medical therapy. Premedicate patients with a prior IRR
before subsequent infusions. Premedication may include acetaminophen,
an antihistamine, and a corticosteroid.

Increased toxicity in the presence of severe renal impairment: The
frequency of ≥Grade 3 adverse reactions and deaths was greater in
patients with severe renal impairment compared to patients with normal
renal function. Avoid use in patients with severe renal impairment.

Increased toxicity in the presence of moderate or severe hepatic
impairment: The frequency of ≥Grade 3 adverse reactions and deaths
was greater in patients with moderate or severe hepatic impairment
compared to patients with normal hepatic function. Avoid use in
patients with moderate or severe hepatic impairment.

Hepatotoxicity: Serious cases, including fatal outcomes, have
occurred in ADCETRIS-treated patients. Cases were consistent with
hepatocellular injury, including elevations of transaminases and/or
bilirubin, and occurred after the first ADCETRIS dose or rechallenge.
Preexisting liver disease, elevated baseline liver enzymes, and
concomitant medications may increase the risk. Monitor liver enzymes
and bilirubin. Patients with new, worsening, or recurrent
hepatotoxicity may require a delay, change in dose, or discontinuation
of ADCETRIS.

PML: JC virus infection resulting in PML and death has been
reported in ADCETRIS-treated patients. First onset of symptoms
occurred at various times from initiation of ADCETRIS therapy, with
some cases occurring within 3 months of initial exposure. Other
possible contributory factors other than ADCETRIS include prior
therapies and underlying disease that may cause immunosuppression.
Consider PML diagnosis in patients with new-onset signs and symptoms
of central nervous system abnormalities. Hold ADCETRIS if PML is
suspected and discontinue ADCETRIS if PML is confirmed.

Pulmonary toxicity: Noninfectious pulmonary toxicity events
including pneumonitis, interstitial lung disease, and acute
respiratory distress syndrome, some with fatal outcomes, have been
reported. Monitor patients for signs and symptoms, including cough and
dyspnea. In the event of new or worsening pulmonary symptoms, hold
ADCETRIS dosing during evaluation and until symptomatic improvement.

Gastrointestinal (GI) complications: Acute pancreatitis,
including fatal outcomes, has been reported in ADCETRIS-treated
patients. Other fatal and serious GI complications, including
perforation, hemorrhage, erosion, ulcer, intestinal obstruction,
enterocolitis, neutropenic colitis, and ileus have been reported in
ADCETRIS-treated patients. Lymphoma with preexisting GI involvement
may increase the risk of perforation. In the event of new or worsening
GI symptoms, perform a prompt diagnostic evaluation and treat
appropriately.

Embryo-fetal toxicity: Based on the mechanism of action and
animal studies, ADCETRIS can cause fetal harm. Advise females of
reproductive potential of the potential risk to the fetus, and to
avoid pregnancy during ADCETRIS treatment and for at least 6 months
after the final dose of ADCETRIS.

Certain of the statements made in this press release are forward
looking, such as those, among others, relating to the therapeutic
potential of ADCETRIS (brentuximab vedotin) as the foundation of care
for CD30-expressing lymphomas, anticipated publication of data from
ECHELON-1 and anticipated regulatory approval from the FDA and other
regulatory authorities for frontline Hodgkin lymphoma. Actual results or
developments may differ materially from those projected or implied in
these forward-looking statements. Factors that may cause such a
difference include the possibility that the safety and/or efficacy
results of the ECHELON-1 trial in Hodgkin lymphoma will not be
sufficient for publication or to gain marketing approval in the United
States or any other country, that we will be required to amend our
submission for marketing approval or that such submission will be
refused or delayed. In addition, our regulatory plans may change as a
result of consultation with the FDA or other regulatory authorities.
More information about the risks and uncertainties faced by Seattle
Genetics is contained under the caption “Risk Factors” included in the
company’s Quarterly Report on Form 10-Q for the quarter ended June 30,
2017 filed with the Securities and Exchange Commission. Seattle Genetics
disclaims any intention or obligation to update or revise any
forward-looking statements, whether as a result of new information,
future events or otherwise.